Photo-copying machines



INVE'NTOR.I

H. HoRsFALL 3,049,066 PHOTO-COPYING MACHINES 4 Sheets-Sheet 1 Aug. 14, 1962 Filled Jan. 6. 1960 HAR OLD HORS FA LL BY ATT%NEY Aug. 14, 1962 Filed Jan. 6, 1960 H. HORS FALL PHOTO-COPYING MACHINES 4 Sheets-Sheet 2 HAROLD HoRsFALL' Aug. 14, 1962 H. HoRsFALL PHOTO-COPYING MACHINES 4 Sheets-Sheet 3 Filed Jan. 6, 1960 il y INVENTOR: HAROLD HORS FALL Aug. 14, 1962 H. HORSFALL PHoTcoPYmc MACHINES 4 Sheets-.Sheet 4 Filed Jan. 6, 196@ INVENTOR.- HAROLD HORS FALL ATT RNEY 3,049,066 Patented Aug. 14, 1962 3,049,066 PHOTO-COPYENG MACHNES Harold Horsfall, ldharn, England, assigner to Horsfall Engineering Company Limited, a corporation of Great Britain Filed Jan. 6, 1960, Ser. No. 911 Claims priority, application Great Britain Ian. 3, 1959 3 Claims. (Cl. 9577.5)

The invention concerns photo-copying machines.

Photo-copying machines are known in which a document to be copied is progressed around a light source, for example a fluorescent tube, but such machines as are at present in use often suffer from certain disadvantages.

For instance, in some cases the document to be copied may be moved around the light source by means of a plurality of parallel endless tapes 4between which and the source, the document and sensitive paper are progressed. It is usual in such machines for the light source itself to -be rotated, thus giving rise to the necessity for using special electrical contacts for the source. The endless tapes may vary in length as a result of atmospheric humidity variations and, since the endless tapes move about rollers which are in fixed spaced part parallel relationship one to another, a difference in effect upon different individual tapes, will give rise to a non-uniform tension in the tapes and thus will effect the quality of the photoprint obtained. Further, such differential tension across the width of the machine may give rise to unsatisfactory stresses applied to the light source with possible fracture arising therefrom.

A further feature of known machines is that a variable speed motor is often used in order that the speed of the photo-copier may be varied. Such a motor is subject to surging with the result that parts of the photographic paper are over or under exposed.

It is among the objects of the present invention to provide a photo-copying machine which will not suffer from these disadvantages, which produces a print of high technical quality and which is compact.

According to the present invention a photocopying machine consists of an extended light source, a freely rotatable transparent sleeve about said light source, a flexible document conveyor structure which contacts said sleeve over the greater part of its periphery and between which and the sleeve a sensitive paper and document to be copied may be passed, means whereby said flexible document conveyor structure may be held in such contact and means whereby said flexible document conveyor structure may be progressed around said light source.

The phrase a freely rotatable sleeve about said light source is to be construed in this specification and claims appendant hereto as meaning a sleeve disposed about said light source and capable of a slight lloating motion transversely of the said source.

Preferably according to the invention, the flexible document conveyor structure is in the form of a plurality of endless bands so disposed about the tube and means for progressing the ilexible document conveyor structure as to present the sensitive paper and document in contact therewith for exposure to said light.

More particularly according to the invention said light source consists of one or more fluorescent tubes and said progressing means of a roller which is driven, through a reduction gear and intermittent driving means, by a constant speed motor, roller speed variation being obtained by a variation in the stroke of the intermittent driving means.

The invention will now be described further, by way of example only, with reference to the accompaying drawings which show two particular embodiments thereof, and in which:

FIG. l shows, in front elevation, a preferred embodiment of the present invention, part of the casing being cut away;

FIG. 2 is an end elevation corresponding to FIG. 1 again with part of the casing removed;

FIG. 3 is a plan View of the arrangement shown in FIGS. 1 and 2;

FlG. 4 is a perspective view of the rollers and tube showing the disposition of the ilexible document conveyor structure thereupon;

FIG. 5 shows, in end elevation, an alternative embodiment, and

FIG. 6 is a front elevation of part of the embodiment of FIG. 5.

Referring now to FIGS. 1 to 4 of the drawings a photocopying machine consists of an extended light source 11, a freely rotatable transparent sleeve 12 thereabout, a system of rollers 13, a flexible document conveyor structure 14 and means 15 whereby said apron may be caused to be progressed around said rollers and said sleeve.

The extended light source 11 is preferably a fluorescent ultra violet tube 11a of Si)` watts power and is five feet long. Around the fluorescent tube is placed a sleeve 12 of transparent or translucent material, the length of the sleeve l2 being approximately four feet six inches, and said sleeve 12. is freely rotatable about the fluorescent tube and has an internal diameter slightly in excess of the external diameter of the tube to allow a limited amount of movement transversely thereof.

The light source 11 is held rigidly in a horizontal position by means of two brackets 16, 17 one close to either end of the tube 11a, to which the tube 11a is secured `and which are themselves secured to a framework 1d 1n contact with the sleeve 12 are two rollers, an upper roller 13a, disposed vertically above the light source, and lower roller 13b, at the same horizontal level as said source. A weighting roller 13e is located below the light source, said roller 13C being horizontally positioned by the engagement of the ends 19 of the roller in vertically disposed guides 2d secured to the framework 18. The weighting roller 13e comprises a shaft 21 carrying a plurality of individual loading sleeves 22 separated by collars 23, the functions of the collars 23 being yet to be described.

The llexible document conveyor structure 14 is in the form of a plurality of endless bands 14a the bands being close together and extending over substantially the full width of the sleeve 12. When positioned upon the system of rollers 13, the endless bands 14a pass around the greater part of the periphery of the upper and lower rollers 13a, 13b and also around the periphery of the sleeve 12 `and thus by virtue of the tension applied to the bands by the weighting roller 13C, draw the sleeve 12 into contact with said upper `and lower rollers. This arrangement is best illustrated in FIGS. 2 and 4. The endless bands are `formed from polyvinyl chloride, although other materials are equally applicable.

The upper and lower rollers 13a, 13b respectively, are rotatably supported upon the framework 18 by means of Oilite bushes 24, said bushes 24a at one end of the machine, being screw-threadedly engaged with the framework thus to facilitate the stripping down of the machine and having a knurled outer end.

A `feed platform 25 extends along the front of the machine and is pivotally secured at its extremities to the framework 18. The platform 25 comprises an opentopped container portion 25a into which the document and sensitive paper may be placed for support and a horizontal position 25b upon which the document and paper may be smoothed before being offered to the nip between the upper roller 13a and the sleeve 12.

The remote edge of the horizontal portion Z'ob when the feed platform is in an operative position extends close to the said nip to facilitate entry thereto of the document and paper.

A stripper plate 26 is located below the Ifeed platform 25, (see FIG. 2), the remote edge 26a of said plate 25 lying closely adjacent the surface of the sleeve 12 on the discharge side of the nip between the sleeve and the lower roller 13b. The stripper plate is cylindrical and of sheet metal. For ease of servicing the stripper plate 26 is pivotally secured to the framework 1 3 by pegs 217, and when in position rests upon further pegs 23 which allow of the desired location of the edge 26a of the plate 26 relative to the sleeve.

A back plate 29 defines the rear wall of a discharge cavity 30, the upper edge of such plate lying closely adjacent the bands 14a, where the latter leave the surface of the lower roller 13b.

The means 1S whereby the flexible document conveyor structure may -be progressed around the system of rollers 13 comprises a constant speed motor 3l driving a shaft 33 through a suitable gearing represented by the part afforded the reference numeral 32. The shaft 33 carries a cranlowheel 34 to which is secured in conventional manner a crankarm 35. A further rigid element 36 is secured in parallel spaced apart relationship relative to the crank arm by means of brackets 37.

Mounted in the casing 376 of the machine for sliding motion in a vertical direction is a U-shaped element 39 carrying, adjacent its remote end, a carrier peg 4t) haying a through hole therein. The carrier peg is disposed across the open end of the element 39 and the axis of the through hole lies in a vertical plane. The peg 4% is so secured to the element as to be freely rotatable about its longitudinal axis. The hole in the peg 4t) is of such dimensions as to receive the crankarm 35 there through.

A U-shaped bracket 41 is secured to the framework 18, said bracket 41 being vertically above the element 39, the parallel limbs of the bracket having elongated slots 42 longitudinally thereof. The further rigid element 36 carries a traveller 43 thereupon, said traveller 43 having lugs 44 extending therefrom which engage the slots 42.

The relative positions of the crankarm 35 the rigid element 36, the U-shaped element 39 and the bracket 41 are such that the substantially vertically disposed crankarm and rigid element lie between the arms of the substantially horizontally disposed U-shaped element 39 and the bracket 41.

Pivotally `supported on the lugs 44 is a fork member 45, the legs 45a of the fork member being disposed outwardly the bracket 41 and there engaging said lugs. The remote end of the fork member 45 is pivotally secured to a known roller type uni-directional drive which comprises a sleeve 46 disposed about an element 47 to be rotated, a wedge formation 48 on the inner surface of the sleeve 46, a contact member 49 located in abutment with said wedge formation 48 and means whereby said sleeve 46 may be angularly displaced thus to cause said member 49 to be urged against the surface of the element 47 to be rotated to rotate same. Angular displacement of the sleeve 46 in the reverse direction releases the pressure between the contact member 49 and the wedge formation 43, the member moving down the wedge, and allows relative motion therebetween. Repeated angular displacement will effect an intermittent drive to the element 47.

r[The required repeated angular displacement of the sleeve is effected by means of the fork member 45 in a manner yet to be described.

The rotation of Ithe lower roller 13b is by virtue of the rotation of the element 47, the latter having a short square shaft l) connected thereto which engages a complementary hole 51 in the end of said lower roller.

The drive to the roller 13b is such that the rotation of the crank wheel 34 causes the crankarm 35 to execute a limited pivotal motion about the carrier peg 40 in the U-shaped element 39, the remote end of said crankarm, and thus the corresponding end of the further rigid element 36, executing a rotary motion. The diameter of the path traversed by the end of the rigid element 36 is dependent upon the relative lengths of crankarm above or below the carrier peg 40.

The rotary motion of the upper end of the rigid element 3e is translated, by means of the engagement of the carrier with the slots 42, into a horizontal reciprocatory motion and thus the sleeve 46 of the uni-directional clutch arrangement undergoes repeated limited angular displacement. Consequent upon such displacement the square shaft 5t) applies an intermittent motion to the lower roller 13b.

In order to increase or decrease the angular speed of the lower roller the slideable element 39 is moved up or down relative to the crank wheel 34, the stroke of the fork member 45 being increased or decreased accordingly.

A knob S2 is secured to the U-shaped element 39, said knob protruding through a vertical slot 53 in the casing 3S of the machine, said slot 53 being appropriately graduated to indicate the rate of rotation of the lower or driving roller 13b.

In operation a document and sensitive paper in contact therewith are placed in the container portion 25a of the feed platform 25 and one edge of the document and paper, hereafter referred to for convenience as the document, is placed upon the horizontal portion 25h. The feed platform is in an inoperative position at this stage, the remote edge of the horizontal portion being spaced from the nip between the upper roller 13a and sleeve 12. After ensuring that the document is free from folds or creases the feed platform is swung into an operative position and the edge of the documents, which was protruding over the edge of the platform, introduced into the nip.

By virtue of the rotation of the lower roller, the endless bands are drawn tightly about the sleeve and upper and lower rollers drawing the sleeve into contact with the rollers and thus ensuring an appreciable nip between the adjacent elements. A document introduced into the nip will be continuously progressed around the light source in a series of short intermittent movements and will be discharged from the nip between the sleeve and the lower roller after exposure. The winding lof the document around the sleeve 12 will be avoided by the stripping plate 26, the latter ensuring the exposed document is directed into the discharge cavity 30 for removal for subsequent processing.

I have found that the use of the endless bands in the circumstances hereinbefore described avoids the difficulties attendent upon their more conventional use. The tension applied to the bands by the nip between the sleeve and the upper and lower rollers respectively avoids the troubles associated with the use of bands of slightly different lengths.

The use of collars on the weighting roller will help to Amaintain the correct posi-tion of the apron longitudinally of the machine.

The particular arrangement shown and described possesses very distinct advantages so far as the servicing of the machine is concerned. For example, the upper roller 13a, may be removed, assuming the upper part of the casing has previously been removed, simply by unscrewing the appropriate Oilite bush 24a, displacing the roller and withdrawing same from the endless bands 14a. In a somewhat similar manner the lower roller and the Sleeve may be removed for cleaning.

Referring now to FIGS. 5 and 6 which shows in end elevation, an alternative embodiment of a photocopying machine, which comprises an extended light source 101,

a freely rotatable transparent sleeve 102 about said source, a system of rollers 103, a flexible document conveyor structure 104 and means whereby Isaid apron may be progressed around said sleeve.

As in the embodiment previously described the light source is preferably a fluorescent ultraviolet tube of 80 Watts power and is some five feet long. The transparent tube is of transparent or translucent material, is approximately four feet -six inches long and is of such internal diameter as to be freely rotatable about the tube.

The tube is held firmly in position by means of brackets 105 secured to a rigid framework.

In front of the tube are an upper and a lower rol-ler 106e, 10617 respectively, each of lsaid rollers being of a similar length to the sleeve.

Extending into the space between the rollers 106a, 106b to a position adjacent the sleeve is a horizontally disposed platform 107.

The platform 107 is adapted at its ends, to provide bearing supports for the rollers, there being clearance holes through which the ends of the fluorescent tube pass. The platform 107 is rigidly secured to a backboard 108 thereby to support the machine in an operable position. The width of the platform is approximately six inches and said platform is so positioned relative to the sleeve 102 that the leading edge thereof is approximately tangential to the uppermost part of the lower roller periphery. The upper and lower rollers 106e 106b are easily removable, being supported in bushes which are in screw threaded engagement with the platform or, at least, lugs thereon. The rollers lie parallel and close to the sleeve in such a position that the float in the sleeve, relative to the fixed fluorescent tube, is sufficient to allow it to be brought into contact with the rollers as and when required.

It is to be Iunderstood that the term brought into contact with, when referring to the rollers and the sleeve is to be construed as meaning brought into adjacent positions with a thin fabric therebetween.

A flexible document conveyor structure 104, some four feet wide and approximately two yards long, is provided which passes over the platform 107 at the front of the machine, between the lower roller 106]; and the transparent sleeve 102, around the .back of said sleeve 102 to emerge between said sleeve and the upper roller 106a and nally over the top o-f the upper roller 106:1 to a third rolle-r 108 over which it freely hangs. The apron 104 is weighted by means of metallic rods 109 accommodated in tubular formations provided at either end thereof, said rods fulfilling a dual role of providing a tension in the apron land lalso of reducing the loading of the apron progressing means.

Said progressing means consists of a constant speed motor 110` of the squirrel cage type which is connected, through a reduction gear 111 and intermittent driving means 112, to a gear wheel 113 at the end of the upper roller 106er. The intermittent driving means 112 consists of a pulley 114 mounted on the output shaft 11S of the reduction gears 111, and having a radially directed slo-t 116 thereon, a plate 117 adjustably positioned in said slot 116, a crankarm 118 pivotally connected to said plate 117, a shaft 119 through the other end of said crankarm 118 which shaft 119 also carries a picking arm 120 and a short locating plate 121 whereby said shaft 119 may be positioned relative to said roller 106:1. The crankarm 118 picking arm 120' and locating plate 121 may all turn freely about the shaft 119 but are maintained in correct axial position thereupon. The other end of the short locating plate may pivot about an extension 122 to the upper roller 106a, thus the shaft carrying the picking arm may move in an arcuate manner about the roller axis.

Upon rotation of the reduction gear output shaft 115 the crankarm 118 is caused to execute a reciproca-ting motion with the result that the shaft 119 carrying the picking arm 120 moves to and fro over an arcuate path. By suitably shaping the teeth on the gear wheel 113 and the engagement portion of the picking arm a ratchet effect may be obtained, the gear wheel 113 being moved by the picking arm during movement thereof in one direction only, the engagement portion riding over the teeth during the reverse motion.

The rotation of the upper roller 10aa is thus a discontinuous motion. The speed of rotation may be varied by adjusting the position of the plate 117 in the slotted portion of the pulley 114, thus increasing the stroke of the crankarm.

Switches (not shown) are provided for the light source and for the electric motor. At the edge of the flexible document conveyor structure 104 is a pin 123 which may engage a microswi-tch 124 mounted below the platform of the machine. By appropriately positioning the pin the machine may be automatically switched off after a predetermined length of travel of the apron.

By a suitable choice of weighting rods the tension in the flexible document conveyor structure may be controlled, and the loading on the constant speed motor kept to a minimum.

ln operation, the flexible document conveyor structure 104, since it is moved by virtue of rotation of the upper roller 106a first draws the sleeve 102 into contact with the upper and lower rollers 106rz, 106b and then carries a document to be copied and a sheet of sensitized paper between the sleeve 102 .and lower roller 106b. The tension in the flexible document conveyor structure 104 continuously urges the sleeve 102 towards the rollers 106e, 10619 thus maintaining the document and paper in contact with the sleeve and in an uncreased condition. The platform 107 below the flexible document conveyor structure 104 ensures that the document and paper may be introduced into the nip between the sleeve and the upper roller in an absolutely uncreased condition by virtue of the fact that the flexible document conveyor structure is moving over the platform at the same time as controlling hand pressure is applied to the document.

To prevent the document wrapping itself around the sleeve during its progression through the machine a stripping member may be provided to direct the document from the machine after passage therethrough. The stripping member consists of a wedge shaped wooden strip positioned with its leading edges close to the point at which the ripper roller and the sleeve come into contact; alternatively said member may be a metallic sheet similarly positioned.

After progression of a document through the machine the flexible document conveyor structure must be returned to its initial position. The requirement is effected by drawing said flexible document conveyor structure in the required direction through the machine, the ratchet arrangement allowing such movement. During passage through the machine the flexible document conveyor structure may drift slightly in a longitudinal direction relative to the sleeve but the flexible document conveyor structure can be correctly positioned relative to the sleeve whilst being drawn back through the machine or at a subsequent time. lt may be necessary to remove one of lthe rollers to move the flexible document conveyor structure but suchen operation may be simply carried out.

It is appreciated that more than one fluorescent tube may be used and in no way do I restrict the invention to the particular features described in the above embodiments. An increase in the intensity of the light source will allow of a reduced exposure time with a consequent increase in roller surface speed.

A great advantage of the machine is that its simplicity of construction is such as to allow easy and rapid stripping down for such things as cleaning or part replacement.

It has been found that by means of the machines hereinbefore described in spite of the intermittent motion of the driving roller, a print may be obtained which is of constant quality and which is an excellent reproduction of the original. When considering the first described embodiment the machine will have the very distinct advantage ot being capable of ready and simple speed variation, the actual adjustment being very sensitive. In the preferred embodiment the tension in the individual endless bands over the contact region will be the same, even though there may well be a difference in length of the separate bands. The actual tension, and thus the pressure yapplied to the document and sensitive paper, will be capable of adjustment by the variation of the loading applied to the Weighting roller.

The invention is not restricted to the particular `features of the embodiments hereinbefore described, since alternatives will readily present themselves to one skilled in the art.

I claim:

1 A continuous photo-copying machine consisting of an extended light source, a freely rotatable transparent sleeve about said source, a plurality of endless belts contacting said sleeve over the greater part of its periphery, means for holding said belts in such contact with said sleeve, and means for intermittently advancing said belts around said light source whereby a sensitive paper and document to be copied located between said belts and said sleeve will be advanced intermittently about said light source, said advancing means comprising a roller about which said belts are trained, a constant speed motor, and an intermittent driving means between said roller and motor for moving said roller and hence said belts, during any one of said intermittent movements, ra linear distance less than the dimension ot said document in the direction of travel of the document through the machine.

2. A machine according to claim 1 wherein said intermittent drivingr means includes a unidirectional drive mechanism engaging said roller, a crank arm pivotally connected between said unidirectional drive and said motor, and a supporting member for pivotally supporting said crank arm, said supporting member being movable in a direction generally along said crank arm in order to vary the extent of the intermittent movements of said unidirectional drive.

3, A method of copying a document upon a sensitized sheet under conditions wherein attempting to advance the sheet in a slow continuous movement past a continuously illuminated light source usually results in transverse striations in the copy, the improvement consisting of advancing said document and sheet in a series of intermittent movements past a continuously illuminated light Source, the linear distance traveled by said document and sheet during each of said individual intermittent movements being less than the dimension of said document in the direction of travel of said document and sheet past said light source whereby the aforementioned transverse striations are avoided.

References Cited in the le of this patent UNITED STATES PATENTS 1,744,323 Mayer Jan. 2l, 1930 2,024,678 Brunk Dec. 17, 1935 2,297,573 MacDonald Sept. 29, 1942 2,615,381 `Haeteli Oct. 28, 1952 2,733,644 Taini Feb. 7, 1956 

